1. Field of the Invention
The present invention relates to a micro gravity environmental control apparatus and micro gravity environmental control method, such as a plant cultivating apparatus, an animal raising apparatus, and a plant cultivating method, an animal raising method, a breeding method. An object of the present invention is to provide a micro gravity environmental control apparatus, such as a plant cultivating apparatus, an animal raising apparatus, and a micro gravity environmental control method, such as a plant cultivating method, an animal raising method, a breeding method, capable of cultivating a plant and raising an animal by using soil and also capable of recovering moisture supplied to the soil so as to reuse the moisture, under a weightless environment or a micro gravity environment.
2. Description of the Related Art
At present, an international space station has been constructed, and a commercial space travel has been planned. Conventionally, a mission in the space environment is a mission for a short term by a small number of persons; however, it is considered that a mission for a long term by a lot of persons will be actively performed. As crews stay in the space for a long term, and as a number of crews simultaneously stay in the space, it becomes an important problem to reserve food stuffs. Of course, the food stuffs to be required may be set off from the earth; however, an enormous cost is generated for setting off a large number of food. Accordingly, it is apparent that necessity of self-supply of the food stuffs is generated.
It is also a great problem in the space stay to treat body wastes of the crews and experimental animals. In the case of treating the body wastes in accordance with a chemical method, a great cost is required for setting off an apparatus for the chemical method and maintaining the apparatus. On the other hand, in the case of treating the body wastes in accordance with a microbiological organic matter decomposition which is carried out in the soil or an inner portion of an activated sludge tank, there is an advantage that an organic matter such as a compost or the like obtained in the treating process can be reused for cultivating the plant. However, in using the soil and the liquid in the space, it is necessary to take all possible measures so as to prevent the soil and the liquid from flying in all directions and being flown out. Taking an apparatus required for the measure and a cost for setting off into consideration, this method is under a condition that the method can not be used at present.
Further, it has been known that there is a case where a living thing expresses a feature which has not been found, under the weightless environment and the micro gravity environment. Accordingly, it is considered that a product class improvement of the living thing or a search of new genetic factor gets into full swing in the future by utilizing the micro gravity environment such as the space environment. In the case where the breeding of the living thing utilized in the earth is carried out in the space environment, it is desirable to breed the living thing under the same environmental condition as the environmental condition on the earth except the gravity, that is, a cultivating condition using the soil composed of a lot of living things such as a soil product material or the like.
In the micro gravity environment or the weightless environment such as a space ship, a space station or the like, for example, the following apparatuses have been known, as a plant cultivating apparatus which is necessary for the self-supply of the plant mentioned above, or an experimental device utilizing the plant.
In Japanese Unexamined Patent Publication No. 62-29915, there is described a plant cultivating apparatus in a space ship which has a conical tube body, a plurality of pallet guides extending in an axial direction on an inner wall of the tube body, a light source device arranged so as to be extended in the axial direction within the tube body, and a part for rotating the tube body, mounts a pallet for breeding a plant on the pallet guides from a side of a small diameter portion within the tube body, and moves the pallet to a side of a large diameter portion of the tube body along the pallet guides in accordance with a rotation of the tube body.
In Japanese Unexamined Patent Publication No. 7-289104, there is described a rotary hydroponic cultivating apparatus comprising a cylindrical base body, a plant carrier holding part provided in an inner side of the cylindrical base body in a protruding manner, a drive source for rotating the cylindrical base body, and a breeding water supply pipe for supplying a breeding water to the cylindrical base body.
Further, in Japanese Unexamined Patent Publication No. 2002-154500, there is described a micro gravity rotating apparatus rotating in an outer space, which comprises a rotary shaft placed in a center portion of a casing and in which any one of a line of both end portion and one end portion is rotatably supported to a side of the casing via a bearing and one end is connected to a motor, an arm having one end mounted to the rotary shaft and extending radially, and an optional number of boxes respectively mounted to a leading end of the arm, applying a weight and housing the plant. The bearing is an electromagnetic bearing having a coil which is close to a periphery of the rotary shaft and is mounted to a side of the casing The micro gravity rotating apparatus is also provided with a plurality of vibration sensors arranged close to the periphery of the rotary shaft in the vicinity of the coil and mounted to a side of the casing, and a controller taking signals from a plurality of vibration sensors, detecting a vibration on the basis of a displacement of the rotary shaft, controlling an exciting current of the coil and controlling so as to absorb the vibration.
All of the plant cultivating apparatuses mentioned above relate to a technique of preventing the water and the plant from flying in all directions by being provided with the rotating part so as to generate a centrifugal force.
However, in order to rotate a cultivating room for cultivating the plant, a great power source is required, there is generated a problem in securing the power and a place for installing the power source, and this method is not realistic. Further, since the centrifugal force is generated, it is not possible to expect an effect of product class improvement in the weightless environment.
As the plant cultivating apparatus which does not require a rotating part, there has been known a plant cultivating apparatus described in Japanese Examined Patent Publication No. 7-63275. In Japanese Examined Patent Publication No. 7-63275, there is described a plant cultivating apparatus comprising an artificial light source, a cultivating floor facing to the artificial light source and having a water holding property, a gas circulating device for circulating an oxygen and a carbon dioxide gas between the plants cultivated on the cultivating floor and the animals, and a supplying part for supplying moisture and a nutrient element to the plants. In the artificial light source, an effective light quantum density in photosynthesis of the light irradiating to the plants cultivated on the cultivating floor is equal to or more than a value by which a direction of growth is fixed to a direction toward the artificial light source even in the case of the plant which is placed in the weightless state:
As the plant cultivating apparatus mentioned above, it is possible to structure the apparatus compact in comparison with that having the rotating part, by not using the rotating part. Further, since the rotating part is not provided, the micro gravity environment can be maintained as it is. Accordingly, it is expected that an unexpected effect can be obtained, for example, in view of the product class improvement of the plant or the like. However, the following problems exist.
The plant cultivating apparatus is used only for cultivating the plants, can not be used for the other usage, thereby resulting in poor general-purpose property.
Further, since this apparatus is the cultivating apparatus using the hydroponic cultivation and the gel, it is necessary to isolate in order to control the concentration of the breeding liquid and prevent the microbial contamination and the like, and there is a problem that a great installing place and a great cost are required. Further, since the cultivating apparatus uses the hydroponic cultivation and the gel and can not use the soil, it is impossible to grow the plants under the same environmental condition as that of the earth except the gravity.
Further, in a germination test of wheat carried out in the “Meal”, it was reported that all of sprouting 300 ears were sterile. The reason thereof is pointed out that an ethylene gas stored within a cabin by a high concentration is caused (Journal of Gravitational Physiology, Vol. 7(2), pp 5-8, 2000).
In the plant cultivation under the closed environment such as the space station, it is a great problem that a harmful gas such as the ethylene or the like is accumulated.